The data patterns and the superblock helped to determine the RAID configuration.

We ran an analysis and found that the parity data was intact and sufficient to rebuild the missing drive.

This NAS used the RAID superblock format. The data was formatted in BtrFS,
a new copy on write (CoW) file system for Linux.

Further analysis showed that the file system was intact. Both the chunk tree and root tree were valid. The root tree pointed to
other sub-volume trees which were in good condition. Most sub-volume trees pointed to the save sets of B-Tree leaf nodes which
indicated that many snapshots had been taken.

Solution:

Using the RAID configuration found at the analysis stage, File Scavenger® can reconstruct the 3-drive RAID 5 with one
missing drive. Since BtrFS was supported in File Scavenger version 5, the quick scan mode immediately
detected the BtrFS volume and successfully parsed the file system.

Over 50 sub-volumes were found because multiple snapshots had been taken.

The sub-volumes with the most current data must be manually selected.

Result:

Three sub-volumes with the most current data were restored successfully with less than 1% corruption, mostly due to
bad sectors in the two remaining drives.